Dentifrice



RUDOLPH A. KUEVEB, OF IOWA. CITY, IOWA, ASSIGNOB TO THE PEPSODENT COMP, 0F CHICAGO, ILLINOIS, A CORPORATIONDF INOIS.

DENTIFRICE.

No Drawing.

To all whom it may concern:

Be it known that I, RUDOLPH A. KUEVER,

a citizen of the United States, and a resident of Iowa City, in the county of Johnson and- State of Iowa, have invented certain new and useful Improvements in Dentifrices, of which the following is a specification.

This invention relates to dentifrice, and it IS the object thereof to produce a dentifrice of superior efficiency and beneficial action in the mouth.

The invention has for its objectto obtain the maximum benefit in the operation of a dentifrice from two standpoints-both the chemical action and mechanical action.

It is now well recognized by modern spe cialists that an acid dentifrice, rovided the acidity is inocuous to the teet is advantageous in stimulating salivary flow and increasing alkalinity of the saliva. It is fur-' ther well appreciated thatfalkaline dentifrices are not beneficial. i

The mechanical action of a dentifrice is that of its polishing agent.

Following is a statement of the properties essential'to the efliciency of a polishing agent and essential to its freedom from injurious incidental edects:

(a) Inert; the olishing agentemployed in the dentifrice s ould referably be inert to acids, and not afiected hy the chemical reactions which take place when the dentifrice is used in the mouth. If the polishing agent is alkaline, it is impossible to produce an acid dentifrice, and all the advantages above referred to. of such a dentifrice are at once sacrificed because the bulk of the polishing agent in a dentifrice is necessarily enough to counteract any practical acidity which may .be employed therein.

(5) Solubility; one of the im ortant sources of trouble due to the use 0 dentifrices containing polishing agents is the lodgment under the gum margins of particles of the olishing agent which accumulate and set up irritation and inflammation. This condition is the more serious as the gum p margins are the more infected. In order to counteract this damaging effect, the polishing-agent in the dentifrice should be soluble, so that particles thereof lodged under the um margins will be dissolved by the water of the saliva within a comparativelyshort time after the teeth are brushed. On the other hand the polishing agent is employed 'ticles thereof would he Application filed March 8, 1922. Serial No. 542,185.

for that purpose and muststand up to that dut it is ofno utility to provide an imme lately soluble substance (such for instance as su er of milk) which will not retain its soli form long enough to serve efficientl as a lishing a cut.

Solu ility 1s expres'se customarily by chemlsts in terms of the number of parts of water in which one part of the substance mquestion will dissolve completely at room tem erature. Thus a substance having a solu ility of 1 in 1000 is a substance, one part of which will be completely dissolved in one thousand parts of water and has a very low solubilit as compared with a solubility of 1 in 50. have determined that the solubility of the polishing agent should be less than 1 in 200. In other words it should require more than two hundred parts of water to dissolve one part of the polishing agent, and a very satisfactory solubility would be approximately 1 in 500. This solubility would insure that the polishing agent would stand up to its duty but lodged pardissolved withm a short time after the teeth were brushed.

(c) Hardness: The next point to be considered in connection with the polishing agent is of course its hardness. A polishing agent should be hard enough to serve efiiciently for that purpose, but should not be hard enough to cut the teeth, even though the teeth be violently scrubbed therewith. Hardness is ex ressed b ascale well known to chemists. he har ness .of tooth substance, including dentine cementum and enamel, ranges from 3.5 to 7. lhe average enamel is 5.5 to 6 in hardness. I have determined as a preferable range of hardness for the polishing agent in a dentifrice a figare less than 3.5 and greater than 1.

The dentifrice of my invention therefore may be defined as one wherein a polishing agent is employed which is inert to acid, and therefore may be used in an acid dentifrice: inert to the chemicallreactions taking lace in the month; has a solubility less than 1 in 200, but nevertheless is soluble enough so that particles thereof will not lodge and remain under the gum margins; and has a hardness less than 3.5 and eater than 1.

As an. embediment of e invention in more specific form, 1 have discovered that anhydrous calcium sulphate as a dental polishing agent possesses the combination of combination, would be as follows:

properties which make it of exceedingly superior utility as a polishing agent for a dentifrice.

As a preferable embodiment of the invention, I combine anhydrous calcium sulphate with an acid. The combination produces an acid dentifrice havin allthe advantages thereof and the polishing agent in the combination has each of the properties above described. Thus anhydrous calcium sulphate is (1) inert to the acid and to the chemical reactions of the mouth. (2) Its solubility is 1 in 500, i. e., it will stand up during the tooth brushing operation but will dissolve within a short time from under the gum mar 'ns. (3) Its hardness is 1.7 which is liar enough to make it a good polishing agent .but too soft to cut the teeth.

An illustrative formula for a dentifrice of my invention in an acid form and embodying the new polishing agent in an etficient Parts. Anhydrous calcium sulphate 100 Gums 3 Organic acids or acid salts l0 Glycerine 40 Water 40 Flavoring.

meagre Of course these proportions may be va ried Within wide limits.

In the use of the foregoing dentifrice, the mechanical action of the dentifrice is exceedingly efiicient but not destructive to tooth structure, salivary stimulation is produced, alkalinity of the saliva is increased, by chemical reactions to which the polishing agent forming the body of the dentifrice is inert, and the salivary flow stimulated by the acid reaction of the dentifrice dissolves any particles of the polishing agent lod ed under gum margins, in a short time a ter the teeth are brushed.

Having described my invention, 1 claim:

1-. A dentifrice comprising anhydrous calcium sulphate mixed with suitable binder and flavoring ingredients.

2. A polishing agent for a dentifrice, consisting of anhydrous calcium sulphate.

3. A dentifrice comprising anhydrous calcium sulphate, glycerine and flavoring.

4. An acid dentifrice comprising anhydrous calcium sulphate and an acid ingredient.

In witness whereof, I hereunto subscribe my name this 3rd day of March, A. D. 1922.

RUDOLPH A. KUEVER. 

